Как настроить кнопку в Unity?

Есть вот такой код:

using UnityEngine;
using System.Collections;
// Performs a mouse look.
public class FPSInput : MonoBehaviour
{
    public float speed_run;
    public float jumpPower;
    private float gravity_character;
    private Vector3 move_vector;
    private CharacterController My_controller;
    private void Start()
    {
        My_controller = GetComponent<CharacterController>();
    }
    private void Update()
    {
        PlayerMove();
        Gravity();
    }
    private void PlayerMove()
    {
        move_vector = Vector3.zero;
        if (Input.GetButtonDown("Up"))
        {
            move_vector.x = speed_run;
        }
        if (Vector3.Angle(Vector3.forward, move_vector) > 1f ||
            Vector3.Angle(Vector3.forward, move_vector) == 0)
        {
            Vector3 direct =
                Vector3.RotateTowards(transform.forward, move_vector, speed_run, 0.0f);
            transform.rotation = Quaternion.LookRotation(direct);
        }
        move_vector.y = gravity_character;
        My_controller.Move(move_vector * Time.deltaTime); // Move player
    }
    private void Gravity()
    {
        if (!My_controller.isGrounded) gravity_character -= 20f * Time.deltaTime;
        else gravity_character = -1f;
        if (Input.GetKeyDown(KeyCode.Space) && My_controller.isGrounded)
        {
            gravity_character = jumpPower;
        }
    }
}

он включён в игрока. Но при запуске выходит такая ошибка:

ArgumentException: Input Button Up is not setup.
 To change the input settings use: Edit -> Project Settings -> Input
FPSInput.PlayerMove () (at Assets/FPSInput.cs:28)
FPSInput.Update () (at Assets/FPSInput.cs:21)

Подскажите новичку как настроить кнопку.